I actually could have used one of these last night when I was swapping and backing up my internal HDDs and didn’t have enough space in my case to hold ‘em all. This multi-hard drive enclosure is not really a new kind of product, but it is by far the simplest (and the price is right). They’ve essentially just ripped the HDD cage out of a computer case and are selling it as a separate product, but that’s actually kind of attractive to me. Essentially the only difference is the fan. You plug everything straight into your SATA ports and PSU. Very hacker-ish, and not conducive to reducing cable clutter.
This is pretty much the extreme opposite end of the spectrum from, say, a Drobo or rack-mount hard-drive product, and the price (and functionality) reflects that. You could go in between the two poles with something like this, which is pretty sweet actually, but I can’t say I trust it. This enclosure is basically just a stand for your hard drives, but if you’re out of cage space (as I am) and think exposed computer stuff looks awesome (as I do) then this is a good buy.